Multiple element antenna arrays are employed within multi-channel receivers and also in active and passive receiving arrays. Such antenna arrays are typically fabricated using printed, plated, stamped, or electroformed array elements, where the techniques for forming such elements are known in the art. Such arrays are typically formed on a two-dimensional substrate to form a planar array. However, such two-dimensional topologies have constraints that make a planar array unsuitable for certain antenna applications.
The constraints of a two-dimensional planar antenna array would conceivably be overcome by placing single antenna elements within a volume to create an array having a three-dimensional configuration. However, such three-dimensional topologies have heretofore typically required combinations of monopole or dipole elements, resulting in a large number of individual components. It is problematic to integrate a large number of array elements at precise locations into a 3-D volume, while maintaining a low parts count and thereby achieving a low cost.
Other alternatives have been contemplated in seeking to obtain a higher level of integration, like using periodic structures such as waveguides. But the manufacturing of such devices is specialized, and thus costly. As a result, it has been difficult and/or expensive to create integrated 3-D arrays that use passive and active array multi-channel technology, particularly for integration into a wireless LAN access point.